Advice on huge pH swings

[VJV]

Hi, my tank goes through pH swings as large as 0,7 between night and day. Wondering if anyone experiences such large swings and whether this can be deterimental to acropora.

During the day with just one or two people in the house and the windows open it can get up to 8,6 but at night with everyone home (we are a family of 6 and the tank is in the living room) it drops to 7,9.

i am dosing 2,5L of Kalk per day (system is about 200g) with a Kamoer pump between 00:00 and 10:00am. I am also using a CO2 scrubber with media connected to my skimmer air intake during the whole day.

I am trying to figure out a way to only have the scrubber on at night as this at least should bring down the high pH during the day.

Co2 levels in my room in the winter a couple of hours after the windows are closed rise to 1400ppm (the outside Co2 is around 450ppm, within the health and safety guidelines) si the reason for the swings I believe is identified.

But my main question as I mention at the beginning of the thread is what impact can such large swings have in terms of acropora health and whether anyone experiences similar swings.

Many thanks and kind regards

 

[Acrofiend]

 

[LC8Sumi]

Sounds like a probe issue to me.

 

[Randy Holmes-Farley Verified Community Expert]

IMO, if such a swing is real, it is a sign the tank likely needs more aeration, not just for pH, but O2 is likely low near the very early morning if CO2 is not equilibrating well (which is what a big pH swing means).

 

[LC8Sumi]

I've found that I have to clean and recalibrate my GHL probes (but probably isn't brand specific) every 3-4 weeks to get accurate results. It also has to be in good flow with no air bubbles. I can't believe a reef tank with pH 8.6 to be in good shape honestly.

 

[Randy Holmes-Farley Verified Community Expert]

I've found that I have to clean and recalibrate my GHL probes (but probably isn't brand specific) every 3-4 weeks to get accurate results. It also has to be in good flow with no air bubbles. I can't believe a reef tank with pH 8.6 to be in good shape honestly.

Why not? have you actually seen evidence of pH 8.6 being a problem? My tank regularly ran to pH 8.55 with no issues.

The only issue I'm aware of as the pH gets higher (but still in the mid 8's) is faster abiotic precipitation of calcium carbonate on heaters and pumps.

 

[LC8Sumi]

Why not? have you actually seen evidence of pH 8.6 being a problem? My tank regularly ran to pH 8.55 with no issues.

The only issue I'm aware of as the pH gets higher (but still in the mid 8's) is faster abiotic precipitation of calcium carbonate on heaters and pumps.

I've sometimes hit high 8.4's with my tank & seen precipitation, or at least a slight haziness. It probably depends on Ca/Kh/Mg levels & methods to replenish them as well. Eitherhow, cleaning and recalibrating the probe won't do any harm & might "fix" the problem.

 

[ca1ore]

How would a tank even get up to a pH of 8.6? Mine did a few years ago and it was a bad probe. regardless 0.7 does seem like a big swing. Mine goes from 7.8 at night to about 8.1 during the day.

 

[Randy Holmes-Farley Verified Community Expert]

How would a tank even get up to a pH of 8.6? Mine did a few years ago and it was a bad probe. regardless 0.7 does seem like a big swing. Mine goes from 7.8 at night to about 8.1 during the day.

Inadequate aeration during the light cycle or the use of high pH additives.

 

[DaneGer21]

My max is 8.31, and my min is 8.04(past month via apex). I see no issues, even yours at twice the swing of mine, I doubt any major issues would arise.

 

[Randy Holmes-Farley Verified Community Expert]

My max is 8.31, and my min is 8.04(past month via apex). I see no issues, even yours at twice the swing of mine, I doubt any major issues would arise.

Not from pH. But the pH swing is indicative of inadequate aeration and O2 may be getting very low.

 

[VJV]

Thanks. I also subscribe to this Chanel.

 

[VJV]

Sounds like a probe issue to me.

thanks, but the probe is calibrated

 

[VJV]

IMO, if such a swing is real, it is a sign the tank likely needs more aeration, not just for pH, but O2 is likely low near the very early morning if CO2 is not equilibrating well (which is what a big pH swing means).

Thia is the problem. I know because i measure the CO2 levels in the living room. As per original post, these reach 1300ppm just a couple of hours after windows are closed and all six of us are in the room and stay at these levels until I open the windows in the morning, coming down to around 500ppm. These room CO2 levels inversely correlate (as they should) to the pH swings. I know why I have them. I just want to know if such large swings affect coral health, specifically acropora.

 

[VJV]

I've found that I have to clean and recalibrate my GHL probes (but probably isn't brand specific) every 3-4 weeks to get accurate results. It also has to be in good flow with no air bubbles. I can't believe a reef tank with pH 8.6 to be in good shape honestly.

The reason it gets to 8,6 is because I am using CO2 scrubbing media in a reactor connected to my skimmer air intake. If i disconnect the reactor the pH won’t go beyond 8,3

 

[VJV]

How would a tank even get up to a pH of 8.6? Mine did a few years ago and it was a bad probe. regardless 0.7 does seem like a big swing. Mine goes from 7.8 at night to about 8.1 during the day.

Pllease see the reply above. It only gets that high when i have the CO2 reactor online. The answer to the swing would be to only use it during nightime but I would need a couple of solenoid valves and a way to split the skimmer air intake into two. I would draw un acrubbed air during the day and scrubbed air at night.

 

[VJV]

Inadequate aeration during the light cycle or the use of high pH additives.

Thanks Randy . Not using any pH additives (other than kalk at night) but the CO2 scrubber is what kicks it during the day to auch high levels. Without it online It only roses to 8,3. BUT, at night it would drop to 7,8 or even 7,7. This is a modern house and once the windows are shut it is pretty airtight so CO2 levels rise prety fast! I jave an idea on how to solve it but what I would like to know is whether there are any studies that show that such large swings are deterimental to coral health.

 

[Randy Holmes-Farley Verified Community Expert]

Thia is the problem. I know because i measure the CO2 levels in the living room. As per original post, these reach 1300ppm just a couple of hours after windows are closed and all six of us are in the room and stay at these levels until I open the windows in the morning, coming down to around 500ppm. These room CO2 levels inversely correlate (as they should) to the pH swings. I know why I have them. I just want to know if such large swings affect coral health, specifically acropora.

My opinion on pH swings are that as long as the low isn't too low (below 7.8 or so), it is not an issue.

My thought on low O2 are different, and I'm concerned for this tank.

 

[VJV]

My opinion on pH swings are that as long as the low isn't too low (below 7.8 or so), it is not an issue.

My thought on low O2 are different, and I'm concerned for this tank.

Please do let me know! Would love to know what you think! I have a lot of surface agitation and my feeling is that at night with the very high levels of CO2 in the living room it equalizes quickly and the pH drops. During the day as I aerate the living room and CO2 levels drop to normal (450-500ppm) levels the pH quicky rises... But these are just my observations.

 

[Brian_68]

My ph drops about 0.2 if the co2 goes above 1000 ppm. I crack a window year round since my house is too tight and run the skimmer air outside. To me it is best not to allow large swings of co2 throughout the day due to the large impact it does have on ph.